I really can't recommend this short story enough: Go, now, and read Seanan McGuire's new "Spores."
Creepy, disturbing and grim... which, of course, describes much of McGuire's work. That's a compliment, of course: I have most enjoyed her work as Mira Grant, first in the Newsflesh series and later with the new Parasitology series.
I've written about Newsflesh before, of course: Not only are journalists heroes for once, but it's a brilliant take on a zombie world without relying on gore and guts. I was so entranced with the first Parasitology book (Parasite) that I ended up spending a five-hour layover in Chicago doing nothing else but reading it. The new book has recently come out, and you'd better believe it's on the post-Christmas buy list.
In the meantime, McGuire's "Spores" was part of an anthology titled The End is Nigh, and it's fun enough to make me seek out the whole book. Go read it for free, and if you're a Hugo voter... well, hint hint.